Spara tid & pengar
The voucher system is ridiculous - like many people I'd imagine, we booked this while on holiday so did not have access to a printer. We emailed to ask whether a PDF on a smartphone would be OK and then received a highly impersonal and unhelpful reply.
We received a voicemail from Shuttle Direct one hour before our taxi arrived, saying that we were not at the designated stop nor could they find us at the hotel. We believed that we had missed the taxi. Only after calling (and using up a lot of credit on a foreign call) did they say that the taxi would be there for the next hour. This caused hugely unnecessary panic.
Taxi driver was excellent, very safe compared to the majority of Moroccan drivers, and the car was comfortable. He accommodated toilet breaks and helped with luggage, was on time and generally very nice.